Wikipedia one of many going dark in SOPA protest

If you're planning to look something up on Wikipedia, you better do it soon. Wikipedia is one of a growing list of sites taking part in an intentional blackout to protest a pair of anti-piracy bills in Congress that some say would harm free speech.

"You've got to do what you believe," Wikipedia founder Jimmy Wales said.

That's why the online encyclopedia will shut down for 24 hours to protest SOPA, the Stop Online Piracy Act, a bill that pits the innovators of Silicon Valley against the entertainers of Hollywood.

The legislation would let a judge require web companies to take down links and stop credit card payments to sites accused of violating a copyright.

The backlash against it is growing.

"There was millions of people protesting all across the nation in the Occupy movement; well what is happening on the Internet is the same type of movement," Wales said.

Wikipedia is joining over a dozen well-known sites, and perhaps hundreds of smaller ones, all shutting down for one day.

"It was pretty awesome, it was pretty exciting just to see that such a big player is getting behind this," Reddit General Manager Erik Martin said.

Reddit is urging visitors to call members of Congress and express their disapproval.

"This is a really big deal and this is something we're going to fight and this is something we think threatens the entire tech sector," Martin said.

There are really two bills -- SOPA in the house, and one in the Senate called the Protect Intellectual Property Act (PIPA) that's co-sponsored by both California senators.

Backers say it's not censorship, but rather a tool to fight bootleg movies and music hosted on foreign websites.

"These rogue sites are hurting American jobs, stealing American jobs, they're harming American consumers and they have no business being on the Internet," U.S. Chamber of Commerce spokesperson Steven Tepp said.

The U.S. Chamber of Commerce says it's worked with the bills' authors to remove language affecting American websites.

"So I'm not sure what these people are protesting anymore, they got what they asked for," Tepp said.

But Palo Alto Congresswoman Anna Eshoo says the bill is still too vague and wants colleagues to vote against it.

"And really pull up the emergency brake on this legislation that in my view has been moving far too fast and without the kind of scrutiny that it deserves," Eshoo said.